U.S. Pat. Nos. 2,924,952; 3,222,035 and 3,365,903 disclose prior art devices for proportioning liquid comestible with air en route from a liquid comestible tank to a freezing chamber in which the liquid comestible and air are blended and cooled to a serving consistency. The prior art devices do not achieve accurate proportioning, primarily because these prior art devices add air to liquid comestible in a single tube. This can create air bubbles in the liquid comestible in the combined air and liquid fill tube of the prior art and result in irregular feed and improper proportions thereof.